I have a 450d which i use with a 100-400 l for long range shows. Its only in this respect that i ask for opinions. Blow for blow of course im sure my larger sensor dslr is capable of beter results. however in the specific situation such as birds where the final image is always a crop, with the sx40 at full zoom would the sx40 give mor detail because of the extra reach or would the larger cleaner sensor of the 450 give mor detail when pixel peeping. Could it be you get more detail but a blurrier image (less sharp)?